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History of Congress and the Capitol

This is the story of one of the world's great experiments in government by the people.

For more than two centuries, a new Congress has convened every two years following elections that determine all the seats in the House and one-third of those in the Senate. While the individuals change, the institution has endured-through civil and world wars, waves of immigration and great migrations, and continuous social and technological change.

The Congress we know today was created after the failure of a government under the Articles of Confederation, which left most powers to the states. In 1787, a convention of specially selected delegates proposed a new constitution that strengthened the national government and established a representative branch composed of a House and Senate.

From the beginning, the two bodies of Congress were meant to be different, yet interdependent. James Madison said they would be "as little connected with each other, as the nature of their common functions, and their common dependence on society, will admit." As a result, the House and Senate have different rules, traditions, and cultures. Yet in their shared responsibilities they function as the nation's single lawmaking body.

Following the War of 1812, a stronger sense of national unity emerged in the United States. As America expanded westward, however, attempts to spread slavery into those new territories seriously divided the nation.

Through a series of compromises between 1820 and 1850 that allowed slavery in some new states and not others, legislators in Congress held the Union together. But these agreements, intended to calm bitter regional divisions, didn’t end the dispute. While they bought time for the nation's new political institutions to mature and strengthen, they allowed slavery to continue for another generation. America's expansion also took a heavy toll on Native Americans, who suffered numerous broken treaties as their land was taken and much of their various cultures destroyed.

In the same period, Congress passed legislation to survey routes for roads and canals, funded improvement of rivers and harbors, and created a banking system to promote the nation's economic self-sufficiency. In Washington, the first Capitol building was completed, and then quickly outgrown, as eight new states joined the Union.

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In 1839, African captives on the slave ship Amistad mutinied

In 1839, African captives on the slave ship Amistad mutinied; the Supreme Court upheld their right to freedom.

Prints and Photographs Division, Library of Congress

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Mid-Atlantic and Northern states had abundant natural resources for industrial power and production.

Courtesy of The Maryland Historical Society

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The cotton gin made large-scale production of cotton profitable, leading to the expansion of slavery.

Prints and Photographs Division, Library of Congress

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U.S. forces invaded Mexico in 1846, claiming nearly half of Mexico’s territory for the United States. Here, General Scott enters Mexico City with his troops.

Prints and Photographs Division, Library of Congress

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Prospectors rushed to California and Colorado following gold discoveries in 1848 and 1859.

Prospectors rushed to California and Colorado following gold discoveries in 1848 and 1859.

Seaver Center for Western History Research, Los Angeles County Museum of Natural History

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The woman suffrage movement officially began at this meeting in Seneca Falls, New York, in 1848.

The woman suffrage movement officially began at this meeting in Seneca Falls, New York, in 1848.

Culver Pictures

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The Erie Canal, completed in 1825, provided passage from the Hudson River to Lake Erie.

The Erie Canal, completed in 1825, provided passage from the Hudson River to Lake Erie.

Reproduced from American Scenery, by Nathaniel Parker Willis, General Collections, Library of Congress

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Treaties with Indian Nations

Early treaties between the United States and Native Americans were acts of nation-to-nation diplomacy. Trade agreements were forged with Indian nations in hopes of discouraging alliances with France or Britain. As settlers moved westward, however, they placed pressure on the federal government to urge tribes to abandon the land. In 1830, Congress passed the Indian Removal Act, giving the president power to negotiate "removal treaties," under which Indians were often made to give up lands in exchange for reservations.